Road grooving process and apparatus



June 23, 1970 G. E. PERKINS 6,

ROAD GROOVING PROCESS AND APPARATUS Filed May 16, 1968 9 v F N a c; 1 W- I k l United States Patent 3,516,339 ROAD GROOVING PROCESS AND APPARATUS Glen E. Perkins, 1428 40th Ave., Rock Island, Ill. 61201 Filed May 16, 1968, Ser. No. 729,724 Int. Cl. E01c 23/16 US. Cl. 94-45 6 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for forming longitudinally extending grooves in a concrete road by drawing over and pressing onto a newly laid concrete road a molding bar extending transversely of the road, the bar carrying a plurality of spaced downwardly projecting ribs disposed longitudinally of the road.

The United States Bureau of Public Roads has ascertained that the provision of longitudinally extending grooves in the surface of a highway will impart tremendous resistance to vehicle skidding, even under adverse driving conditions such as a heavy rain, and it is the object of the present invention to provide a novel method and means for the formation of such grooves in a concrete pavement by molding said grooves thereinto while the road is still in a plastic condition across the full width of the road or at one or both of its edge portions as desired or required.

At present, longitudinally extending grooves are being cut into a highway surface such as a concrete surface after it has been set, with diamond type saws, the grooves being of V-shape, one-quarter inch deep, three-eighths inch wide and at a spacing of one inch. While this method is satisfactory, it is obviously quite expensive.

It has also been proposed to provide grooves in asphaltic roads while still plastic by means of drag pins or wheels. However, the employment of such devices with unset asphalt or wet concrete would cause a build-up of the material adjacent the drag pins or wheels leaving an irregular surface with no way of smoothing it out unless the grooves are refilled.

In accordance with the present invention, I provide novel molding bars which are adapted to extend transversely of the road and which are provided on their underface with a plurality of spaced downwardly projecting ribs disposed longitudinally of the road and by a pressing operation there is a simultaneous formation of the grooves and smoothing the intervening surfaces therebetween so as to conveniently, economically and quickly form a grooved smooth road surface. The molding bar employed may be as a final component of a continuous or slip form road building or paving machine such as described in US. Pat. No. 2,976,783, and in association with a machine of the class described as a final element and if desired in association with the vibratory component thereof. In the alternative, it can be employed as a separate unit on the aforesaid or other paving machines or adapted for use as a separate device following such paving machines while the paving is still in the plastic condition amenable to indentation or grooving by the molding bar of the present invention.

Other objects and advantages of the present invention, its details of construction, arrangement of parts and method thereof will be apparent from the following specification and accompanying drawings wherein,

FIG. 1 is a diagrammatic side elevational view of a slip form road building or paving machine such as shown and described in the aforesaid patent.

FIG. 2 is a transverse section on the line 2-2 of FIG. 1.

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FIG. 3 is a fragmentary bottom view of the groove molding bar of the present invention.

FIG. 4 is a section on the line 4-4 of FIG. 3.

FIG. 5 is a fragmentary perspective top elevational view of the groove molding bar of the present invention.

FIG. 6 is a fragmentary perspective view of a longitudinally grooved road surface made in accordance with the present invention.

Referring to the drawings, the reference numeral 10 generally designates a slip-form road building or paving machine such as that more fully described in US. Pat. No. 2,976,783 and which can be employed with the device of the present invention, namely the groove molding bar 11 as a final element.

Although not restricted thereto since I have previously indicated that my groove molding bar can be operatively associated with other paving machines or adapted for use as a separate device, the paving machine ll) of FIG. 1 comprises a frame portion 12 supporting driving mechanism comprising an internal combustion engine 13 driving a sprocket wheel 14 through a suitable clutch mechanism (not shown) by lever 15 and sprocket chain 16. The sprocket chain 16 is trained about sprocket wheel 17 carried on the input shaft of a conventional gear transmission, more fully described in said Pat. No. 2,976,783. controlled by gear shift lever 18 for changing the speed of the output shaft (not shown).

The frame portion 12 comprises spaced transverse and spaced longitudinal beams joined to opposite slip forms 7 about which are disposed the articulated tracks 8 engaged at their opposed ends about the sprocket wheels 9 driven through engine 13, and which may be driven jointly or separately as is well known. At the forward portion of frame 12 of the machine a transverse beam and scraper blade assembly 19 is carried which first levels off Portland cement concrete deposited thereat during forward movement of machine 10 to form a relatively fiat mass of concrete having a width equal to the distance between the slip forms 7 and a height which may be substantially flush with the upper edges of said slip forms. The resulting road mass is then densified by vibrator means 20 such as a vibratory screed 21 supported by the frame 12, and actuated by a vibrating mechanism 22.

The electric vibrating mechanism 22 connected to the vibrator plate 20 imparts vibration to the plate of relatively high frequency and relatively small amplitude. An electric generator, not shown, may be carried upon frame 12 and is driven by any suitable means whereby current may be supplied to the vibrating mechanism 22 through a suitable conductor. The vibration of the road material by the screed 21 densifies the road material mass, and if the mass comprises concrete, fines are brought to the surface of the mass and the heavier aggregate submerged. Thus, the upper surface of the road material mass 6 is brought to a consistency which permits it to be smoothed.

An extrusion meter 5 extending transversely between the forms 7 is positioned beneath the frame 12 rearwardly of the vibrator, the same comprising a generally L'shaped plate having a long horizontal leg adapted to be compressively engaged with the surface of the concrete mass. The extrusion meter 5 is adjustably but rigidly connected to the machine frame 12 so as to bring the total mass of the machine to bear on the concrete through the extrusion meter, thereby to compact and smooth the concrete to essentially the final dimensions of the pavement. The leading edge of the meter 5 is raised slightly whereby the vibrated road material will pass with ease beneath the meter and thereafter be compressively extruded to final dimensions.

Disposed rearwardly of the meter 5 and extending transversely of the machine 10 between the slip forms 7, there is a groove molding or extruding bar or plate 11 which may be substantially in the form of a channel. This bar 11 carries on its underface a plurality of parallel preferably V-shaped ribs 28 and the intervening surfaces of the bar between the ribs 28 is imperforate and smooth.

Extending into the rearward or hollow portion of the transversely extending molding bar 11, I provide a plurality of hydraulic cylinders 29 supported on the frame 12 and adapted, through operating mechanism thereon not shown, to press the molding bar 11 downwardly into firm engagement with the road surface to the depth of the ribs 28 so there is a simultaneous grooving of the road 6 in a longitudinal direction while still in plastic condition and a smoothing of the surfaces between the resulting grooves 30. If desired, the groove molding bar 11 may be hinged or otherwise attached to the rear end of the metering device 5, or in the alternative it may be a wholly separate unit forming the last finishing unit of a road paving machine, or the further alternative as a separate succeeding unit while the pavement is still in a plastic condition. Although the ribs 28 may extend over the full width of the paving machine between the slip form 7, it will be understood that they may be disposed over only a portion thereof such as adjacent the outer edges or in any other suitable pattern desired or required.

In other words, the paving device hereinbefore described comprises a pair of spaced parallel slip forms adapted to be moved forwardly within articulated tracks; a primary strike-off extending between the slip forms; vibrating means behind the strike-off; an extrusion meter behind the vibrating means; and finally a grooving element which is pressed downwardly into firm engagement with the concrete surface, the grooving element comprising a plurality of tapered downwardly extending grooving elements extending longitudinally of the road bed of preselected depth and width located on preselected centers, the pressing being such that the ribs are fully indented into the plastic road surface in a manner whereby the areas intervening between the ribs simultaneously prevents dislocation of the concrete above the predetermined surface and smoothens it as the grooving element is moved or drawn forwardly.

The embodiment shown, by virtue of its hydraulic actuating jacks or cylinders 29, lends itself to grooving selected longitudinal portions of a roadway, especially potentially dangerous areas such as curves, intersections, interchanges, etc., while leaving the rest of the roadway ungrooved. Specifically, the bar 11 could normally be elevated above the concrete surface and be pressed downwardly by said jacks into molding contact with said surface only in those areas where grooving was specified by the highway engineers. On the other hand, if the grooving were to be continuous, the bar could be continuously pressed into molding contact with the concrete. Alternatively, in the case of continuous grooving, the groove molding ribs 28 could be provided directly on the lower surface of the extrusion meter 5, thereby eliminating the separate bar 11 and jacks 29.

Should a different form of groove be desired than the one-quarter by three-eighths inch V groove now deemed advantageous, it is apparent that the ribs 28 can be of different cross sectional configuration, different size and different spacing to attain whatever grooving may be specified. Irrespective of form, it is believed desirable to have the leading edge of each rib tapered and to have the ribs extend to at least the trailing edge, and preferably slightly beyond the trailing edge of the bar or meter on which they are mounted.

As previously noted, it is preferable that the grooving ribs be mounted on or comprise the final concrete molding element of the paving apparatus. However, this does not eliminate or render ineffectual conventional texturing or other final surface treatment of the concrete, such as a burlap or light broom drag. It is specifically contemplated that the grooving means would normally be followed by a burlap drag, which would texture the concrete surface between the grooves but not cause the plastic concrete to be displaced into the grooves.

Thus, while I have shown and described the preferred embodiment of my invention, it will be understood by those skilled in the art that changes may be made in the details thereof without departing from its scope as comprehended by the following claims.

I claim:

1. The method of forming a series of spaced parallel grooves in the surface of newly laid concrete pavement which comprises progressively moving over the pavement a molding plate having an appreciable dimension in the direction of movement and having a plurality of spaced downwardly projecting ribs of shallow depth on the lower surface thereof, and simultaneously pressing said plate against the upper surface of the pavement to imbed said ribs to their full depth in the pavement and to press the intervening areas of said plate against the surface of the pavement with substantial pressure.

2. The method of claim 1 including the steps of confining the concrete while in plastic condition on subgrade between a pair of side forms, progressively moving longitudinally over the confined plastic concrete at molding plate extending transversely of the concrete from side form to side form, and simultaneously pressing said plate against the upper surface of the plastic concrete with sufficient pressure to extrude the concrete between said side forms, subgrade and said plate.

3. Concrete road grooving means comprising a molding member adapted to be disposed transversely of a road, said member carrying a plurality of spaced parallel ribs adapted to be disposed longitudinally of said road, said member and said ribs having an appreciable dimension in the direction longitudinally of the road and said ribs being of shallow depth, the areas of said member between said ribs being smooth and flush with one another, means for pressing said molding member onto a newly laid road while still plastic to fully indent said ribs into the concrete and to press said areas of said member against the surface of the concrete with sufiicient pressure to extrude the concrete, and means for simultaneously moving said member longitudinally along the road.

4. The grooving means of claim 3 wherein said ribs are substantially V-shaped in cross section.

5. The grooving means of claim 3 wherein said ribs are tapered at their forward ends and extend rearwardly to at least the trailing edge of said member.

6. Concrete pavement grooving means comprising a molding member carrying a plurality of depending spaced parallel ribs of shallow depth on the lower surface thereof, the areas of said member between said ribs being smooth and flush with one another, and means for pressing said molding member onto newly laid pavement while still plastic to imbed said ribs therein to their full depth and to press said smooth areas of said member against the pavement surface with substantial pressure and for simultaneously moving said member over said surface, said member and said ribs having an appreciable dimension in the direction of movement thereof.

References Cited UNITED STATES PATENTS 1,650,574 11/1927 Stubbs 9448 1,707,089 3/ 1929 MacKenZie 9445 1,750,107 3/1930 Heltzel 9439 2,049,115 7/1936 Hadley 9446' 2,077,356 4/1937 Day 943'9 2,261,766 11/ 1941 Jackson 9445 2,643,595 6/1953 Jackson 9448 3,406,618 10/1968 Bowman 9445 XR JACOB L. NACKENOFF, Primary Examiner 

